It has been shown that the gain spectrum obtained by cascading two or more semiconductor laser amplifiers (SLAs) can have a ripple amplitude that is significantly smaller than that currently attainable with a single stage of optical amplification. The paper examines the performance of optically preamplified receivers employing cascaded SLAs, emphasis being placed on the influence of signal frequency fluctuations. The analyses make use of a lightwave simulation package designed to accommodate laser chirp, fibre dispersion, laser preamplifiers and receiver characteristics. Our results suggest that cascaded SLAs offer improved receiver sensitivity in the presence of laser chirp compared with a single-stage amplifier of the same net gain and facet reflectivity. The best performance may be achieved when the cascaded preamplifiers are synchronously tuned rather than stagger-tuned, despite the smaller gain ripple associated with the latter case. We have used these techniques to investigate a new approach for cascading SLAs to realise optically preamplified receivers, which are less sensitive to optical signal polarisation. The approach uses a single optical receiver and no additional receiver electronics. The difference in receiver sensitivity for orthogonal polarisations is reduced to 0.7 dB, compared with 4.5 dB for a single preamplifier receiver and at the cost of 1.6–2.3 dB power penalty compared with perfectly matched polarisation for the latter case.